Recent technical advances in molecular biology, including the development of transgenic and gene knockout technologies, have led to increased understanding of the nature of the genetic and epigenetic changes that occur in the development of skin tumors. These advances are greatly improving and expanding our concept of the mechanisms by which normal cells progress to malignancy. The role of both intrinsic genetic factors and external modifiers are now being elucidated. This has led to the identification of several targets for prevention and for therapy, although considerably more advances are needed. The goal of the 6th International Skin Carcinogenesis Conference is to provide a forum for exchange of the most recent and relevant information on the biological, cellular and molecular changes that occur during nonmelanoma and melanoma skin tumor development. Sessions will focus on understanding the genetic factors that can influence skin cancer susceptibility, how alterations in normal cell signaling and proliferation affect the expression of particular genetic alterations, and how intrinsic and extrinsic factors can modify the neoplastic process. This ongoing biannual skin carcinogenesis conference is important for two reasons. The mouse skin paradigm for multistage carcinogenesis has served as a model of discovery where the genetic and epigenetic alterations are applicable to many if not all human epithelial cancers. This is a very highly interactive meeting where it is anticipated that new concepts and ideas will be generated and shared that will have an impact on the prevention and intervention in skin cancer development. Because there is a world-wide increase in the incidence of both melanoma and nonmelanoma skin cancers, new approaches to skin cancer prevention and treatment are needed. This meeting is intended to bring together approximately 80- 100 researchers from major laboratories in the United States, Europe and Japan that are actively engaged in cutting-edge research on the mechanisms of skin cancer development and prevention. The meeting will be held jointly with the Montagna Symposium on the Biology of Skin.